Rule 4 calculator
A horse was withdrawn and your returns came back lighter than you expected. Work out what the deduction should have been — and check your bookmaker got it right.
Enter the price of each withdrawn horse at the moment it came out.
- Returns before
- £50.00
- Winnings before
- £40.00
- Deduction (45p)
- −£18.00
- Winnings after
- £22.00
Rule 4 comes out of winnings only — your stake is returned in full.
How Rule 4 works
When a horse is withdrawn after betting opens and there is no time to form a new market, everyone still in the race has a better chance than the price you took reflected. Bookmakers correct for that by deducting from winnings, using a scale based on the withdrawn horse's price at the moment it came out.
The deduction comes out of winnings only — your stake is returned in full. That is the part most people get wrong when checking the maths by hand: applying the deduction to total returns overstates it every time.
Rule 4 deduction table
The standard Tattersalls scale. Deductions from more than one withdrawal are added together, up to 90p in the £.
| Odds of withdrawn horse | Deduction per £1 of winnings |
|---|---|
| 1/9 or shorter | 90p |
| 2/17 – 2/11 | 85p |
| 1/5 – 1/4 | 80p |
| 2/7 – 3/10 | 75p |
| 1/3 – 2/5 | 70p |
| 4/9 – 8/15 | 65p |
| 4/7 – 8/13 | 60p |
| 4/6 – 4/5 | 55p |
| 5/6 – 20/21 | 50p |
| Evens – 6/5 | 45p |
| 5/4 – 6/4 | 40p |
| 13/8 – 7/4 | 35p |
| 15/8 – 9/4 | 30p |
| 5/2 – 3/1 | 25p |
| 10/3 – 4/1 | 20p |
| 9/2 – 11/2 | 15p |
| 6/1 – 9/1 | 10p |
| 10/1 – 14/1 | 5p |
| Longer than 14/1 | No deduction |
Questions
- What is Rule 4 in horse racing betting?
- Rule 4 is a deduction bookmakers take from winnings when a horse is withdrawn after betting has opened and there is no time to form a new market. The remaining runners' chances improve, so the bookmaker reduces payouts to reflect the shorter effective price you should have been given.
- Is Rule 4 taken from my stake or my winnings?
- From your winnings only. Your stake is always returned in full. A 25p Rule 4 on a £10 bet at 5.0 reduces winnings from £40 to £30, so you receive £40 back rather than £50 — not £37.50, which is what you get if you wrongly deduct from total returns.
- How is the Rule 4 deduction worked out?
- From the price of the withdrawn horse at the moment it was withdrawn, using the standard Tattersalls scale. A short-priced withdrawal means a bigger deduction: 1/9 or shorter takes 90p in the £, while anything longer than 14/1 takes nothing at all.
- What happens if more than one horse is withdrawn?
- The deductions are added together, capped at 90p in the £ in total. Two withdrawals at evens and 3/1 mean 45p plus 25p, so 70p.
- Does Rule 4 apply if I took a price after the withdrawal?
- No. Rule 4 only applies to bets struck before the horse was withdrawn. If you took a price after the market was re-formed, you are betting into the corrected odds already.
- Does Rule 4 apply to each-way and multiple bets?
- Yes. The deduction applies to the winning parts of an each-way bet, and to the affected leg of a multiple — which then flows through the rest of the accumulator.
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Open calculatorStop checking your bookmaker's maths by hand
betr.pro applies Rule 4 automatically when it settles your racing bets, so your P&L and closing line value stay right without you working anything out.